Engine/Transmission (1998.5 - 2002) No Overdrive and WTS issues

[David DeMattia]

Good afternoon, I have a 99 24v Cummins SLT. It will not start until the Wait till Start light illuminates, even when it is warm. (It used to). Also, I have lost 4th gear (yes, it is engaged). Also, I do not get ANY codes. I suspect the ECM and/or Overdrive/Lockup Solenoid. Any advice.

Thank you,

David